Technical Field
The disclosure in generally relates to a non-volatile memory device and method for fabricating the same, and more particularly to a three dimension (3D) non-volatile memory device and method for fabricating the same.
Description of the Related Art
In a non-volatile memory device, for example a NAND flash memory device, a plurality of memory cells are typically connected in series between a source line and a bit line by a mono-silicon/poly silicon based conductive strip; and the mono-silicon/poly silicon based conductive strip may be implanted with ion dopants in order to reduce the series resistance of the cells string in series. However, it is difficult to perform an ion implantation process to dope the mono-silicon/poly silicon based conductive strips of a 3D NAND flash memory device, since these mono-silicon/poly silicon based conductive strips are imbedded in a multi-layer stack including a plurality of the conductive strips and a plurality of insulating layers alternately stacked along the vertical direction. To delivering ion dopants into these mono-silicon/poly silicon based conductive strips imbedded in the multi-layer stack may make the process for fabricating the 3D NAND flash memory device more complicated than that for fabricating a two dimension (2D) NAND flash memory device; and the thermal budget for 3D NAND flash memory device could be significantly increased. Besides, the ion implantation is nearly isotropic, thus the dopants that are diffused in an undesirable direction may inversely affect the erase/program operation of the 3D NAND flash memory device. In the worst case, it may lead the 3D NAND flash memory device failure.
Therefore, there is a need of providing an improved memory device and method for fabricating the same to obviate the drawbacks encountered from the prior art.